Anonymous messaging app Kik is under heavy scrutiny because of its association with the murder of 13-year-old Nicole Lovell.

The Virginia middle schooler was messaging 18-year-old David Eisenhauer, a Virginia Tech freshman on the app.

CNN reported that investigators believe Eisenhauer and Lovell had an inappropriate relationship. When she threatened to go public with their relationship, police believe he kidnapped and stabbed Lovell to death.

Another freshman, 19-year-old Natalie Keepers, was denied bail Thursday and remains in jail for being an accessory before and after the crime, as she allegedly helped Eisenhauer hide Nicole's body.

Here is what parents need to know about Kik to protect their children and teens.

Kik is an anonymous messaging app. It is unlike other popular messaging platforms like Facebook Messenger and WhatsApp in that users can make a an anonymous profile. Users are identified only by a username they create when they sign up. The app press page says it is used by over 40 percent of U.S. teens.

Usernames can be searched. The site recommends users create a username that is hard to figure out, but many teens have their Kik usernames on their public Twitter pages and Instagram feeds. ABC News reported that users can search "Kik user" and find lists for usernames sorted by gender. Once a user discovers a username, they can message that person.

Teens need parent or guardian permission to use the app. Teens ages 13 to 18 need permission to sue Kik. Teens under 13 are prohibited from the app. "If Kik obtains knowledge that a user is under the age of 13, it’s our policy to permanently deactivate their account and delete their personal information," according to Kik FAQs. There is also no way to verify users ages.

Parents can disable the app. There is a roundabout way parents can disable Kik and other apps from their teen's phones. On the iPhone, parents can use restrictions to limit specific apps and features, including installing apps, with the settings app under general and restrictions. Google Play apps can be disabled in the apps or application manager section of the device's settings app.